最新刊期
卷 0 ， 期 0 ， 2020
- 摘要：Aromatic electron donor-acceptor foldamers (aedamers) are a kind of macromolecules often folded into pleated structures via a driving force of complementary electrostatic interactions,which mainly includes three key elements: an electron donor (such as 1,5-dialkoxynaphalene,Dan),an electron acceptor (such as 1,4,5,8-napthalenetetracarboxilic acid diimide, Ndi),and a flexible-linker separator. The folding architectures of aedamers are formed though molecular self- assembling on the level of secondary structures/conformations, also with an increasing research highlight of self-healing functions. Based on the above background, the aedamers were roughly reviewed in this article, focusing on their chain structures, intra-/inter-molecular donor-acceptor synergistic interactions, folding architectures,formation mechanisms,and self-healing functions.关键词：Aromatic electron donor-acceptor foldamers (aedamers);Synthetic foldamers;π-π;Interactions
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发布时间：2022-09-18 - 摘要：Epichlorohydrin rubber had come out earlier. Its excellent properties were made its rapid development, and had been widely used in automotive,electronics and aerospace fields. In recent years, its unique conductivity was widely used in the office automation machines so it became the hot research. The progress on the synthesis and applications of epichlorohydrin rubber was reviewed in this paper. Based on the molecular structure of epichlorohydrin rubber,the properties、applications and the simple explanation of the mechanism of rubber conductive were summarized in recently researches. Through analysis of catalytic system used,the composition, characteristics and developments were described. Meanwhile, the prospect of epichlorohydrin rubber was presented.关键词：Epichlorohydrin rubber;Structural analysis;Catalytic systems;Trends
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发布时间：2022-09-18 - 摘要：Adding graphene (G) as nanofiller in electrospinning nanofibers is helpful to improve the properties of polymer nanofiber and expand its application fields. This paper introduces the development of G composite nanofibers prepared by electrospinning in recent years at home and abroad, focusing on graphene with polyamide(PA),polymethyl methacrylate (PMMA) , polyacrylonitrile (PAN) and titanium dioxide (TiO2 ) composite nanofibers as well as theirs application in the fields of photocatalyst, supercapacitor,dye-sensitized solar cells (DSSCs),nano-sensors,biomedical, etc. The prospects of G composite nanofibers have also been described.关键词：Electrospinning;Graphene;Nanofibers;Composite
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发布时间：2022-09-18 -
Factors Influencing Ionic Conductivity and Stability of Anion Exchange Membranes and Recent Progress
摘要：According to the principal of anion exchange membrane-direct methanol fuel cell (AEM-DMFC) and the molecular structure and mechanism of ionic conductivity from multi-scale (molecular structure and aggregation structure) of AEM, this paper elaborate the main factors influencing AEM ionic conductivity and stability. Two main strategies to balance ionic conductivity and stability were summarized among recent advanced AEM studies. Including regulating AEM performance by designing of backbone and side chain structure,or preparing different multiphase composite AEM through different approaches.关键词：Anion exchange membrane;Mechanism of ionic conductivity;Stability- 2
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发布时间：2022-09-18 - 摘要：The adsorption and remove of heavy metal ions is still a real challenge in water treatment. Research for novel adsorbents with excellent properties is the most important issue in remediation of heavy metal pollution. Polyethyleneimine (PEI) is multi-functional polymer material. It was widely used in gene transfer,papermaking,catalysis, flocculant,dye- fixing agent, fiber modification, textile auxiliaries and ion exchange resin. The amine groups of PEI exist in primary, secondary and tertiary forms with a branching site at every 3~3. 5 nitrogen atom in any given chain segment, each with potential to be protonated. Thus, it has a high cationic charge density in acid solution and can form coordination complex with heavy metal ions in neutral or basic solution. As a novel sorbent,PEI has good hydrophilicity, high adsorption capacity, rapid chelating rate, good selectivity and it is also an environment friendly material. The character of PEI has attracted wide attention of researchers, and its applications in detection and adsorption separation fields of metal ions are developing. The adsorption properties of PEI were widely investigated. However, chelating mechanism of PEI was still limited. Mechanism study was summarized including: (1) Coordination process; (2) Electrostatic interaction; (3) Ion exchange effect. On the other side, applications on original PEI were much less due to its leachability and high costs. To solve this problem,research on PEI derivative was developed, including immobilization, grafting and modification of PEI. Moreover, combination of PEI with opto or electrical element to exploit novel photoelectric sensor was also discussed. The aim of this work is give a brief review of research on PEI as novel metal ions adsorbents, as well as its characteristic, adsorption and chelating mechanism. The modification and application of PEI was summarized with emphasis. This review provided a reference for broadening the potential application of PEI and developing new techniques for monitoring and treatment of heavy metal ions.关键词：Polyethyleneimine;Metal ion;Adsorption;Review
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发布时间：2022-09-18 - 摘要：The unique molecular structure of graphene endows it superior physical and chemical properties, which aroused intensive interests of researchers. Various graphene-based composites were prepared by researchers. Among these materials,graphene-based hydrogel is a kind of practical and attractive material with wide application prospects. In this article, we review recent progress on the graphene based hydrogels and their application in supercapacitors,biomedical and water purification. The prospects of the graphene-based hydrogels are also discussed.关键词：Graphene;Hydrogel;Composites
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发布时间：2022-09-18 - 摘要：The researches on degradation and combustion of rigid polyurethane foams (RPUF) were reviewed,based on the degradation of polyurethane foam in different conditions,the regulations of degradation and combustion of RPUF were summarized. On the basis of theory and results in the literature and our research, the influence of phosphorus flame retardants and nano materials on the flame retardant properties of RPUF, including limited oxygen index and heat release rate,was focused. The flame retardant mechanism and regulation of phosphorus flame retardant and the effectiveness of synergy of phosphorus flame retardants and functional fillers on the flame retardant properties of RPUF were summarized. At last, the way to realize halogen-free flame retardant RPUF was indicated.关键词：Rigid polyurethane foam;Halogen-free flame retardant;Phosphorus flame retardant;Functional filler
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发布时间：2022-09-18 - 摘要：The hydrid complex flocculent has been attracted more attention to the researchers and the users, who are seeking the cheap,more safe in ecology and low risk in health, high efficient, and powerful flocculent. Their types, preparation methods, preporties and applications in water treatment have been reviewed,including inorganic/synthesized organic complex flocculent, inorganic/natural polymer complex flocculent and natural polymer graft copolymer. Their mechanisms of flocculation are briefly generalized and analyzed. And some problems and proposals about current inorganic/ organic hydrid complex flocculent are pointed out.关键词：Hydrid materials;Complex flocculent;Inorganic/organic flocculent;Flocculating mechanism;Wastewater treatment
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发布时间：2022-09-18 - 摘要：Synergistic flame retarding system of inorganic flame retardants is an important direction of flame retardant technology. It helps reducing the amount of flame retardant and enhancing flame retardant effects, and it also helps improving the heat resistance, mechanical properties and processability of polymers. A review on the recent progress in synergistic effect of inorganic flame retardants for different polymers was presented in this paper. The mechanisms and effects of synergistic fire retarding of single flame retardant and Synergistic flame retarding system were analyzed,and the synergistic flame retardant system of aluminum-magnesium system and expandable graphite were elaborated. The flame retardant mechanism, proportional allocation, addition amount and the effect of synergistic fire retarding were pointed out in each system. Finally the developing trends of the synergistic flame retardant system of inorganic flame retardants were proposed.关键词：Inorganic flame retardants;Synergistic flame retarding;Polymer;Aluminum-magnesium system;Expandable graphite
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发布时间：2022-09-18 - 摘要：Electrospun nanofibrous membranes(ENMS) have a lot of impressive properties,such as high porosity with small pore size. However, widespread adoption of these materials has been hindered by its poor mechanical strength, which caused by the small diameter and lack of effective junction point between fibers. In this study,a post-treatment was demonstrated to the PAN/PVDF-HFP and PVDF/PVDF-HFP composite ENMS made by blending eletrospinning with a thermostable polymer and low melting temperature polymer. The post-treatment involves a 5min thermal calendering process with a pressures of 3MPa under 110℃. During the treatment,the low melting temperature polymer melted partially to form point bonding, bond the nanofibers together. The experimental results showed that the strength of enhanced PAN/ PVDF-HFP and PVDF/PVDF-HFP composite ENMS was 923. 1% and 665. 7% higher than that before treatment, reaching 17. 8MPa and 26. 9MPa,respectively,meanwhile the high porosity of ENMS have also been kept.关键词：Blending eletrospinning;Thermal calendering process;Point bonding;Mechanical properties;Enhanced nanofibrous membranes
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发布时间：2022-09-18 - 摘要：A truncated Gaussian random filed method was employed to generate three-dimensional reconstructed models of polyolefin catalysts based on the porosity evaluated from absorption method and the correlation function from small angle X-ray scattering (SAXS) method. It has been found that the reconstructed models have the same porosity and the correlation function as the original catalysts. Moreover, the way to obtain the correlation function of three-dimensional form directly from SAXS method is easier than the process that the correlation function extracted from two-dimensional images is expanded into three-dimensional form. And the correlation function from SAXS method is more abundant and accurate than that from two-dimensional images, because the nanoscale resolution is hardly achieved in some ordinary images but can be characterized by the SAXS method which provides more statistics. The three-dimensional models of catalysts establish the basis for calculation on the effective heat and mass transport coefficients such as diffusivity, permeability, and heat conductivity, and for prediction of the catalyst fragmentation.关键词：Polyolefin catalyst;Small angle X-ray scattering;Gaussian random filed method;Three-dimensional reconstructed model
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发布时间：2022-09-18 - 摘要：The synthesis of a chiral liquid crystalline monomer (MLC) derived from menthol,crosslinking agent (CA) and cholesteric elastomer (LCE) is reported. Their chemical structures were characterized with FT-IR and 1H NMR. The liquid crystalline properties and thermal stability were investigated by differential scanning calorimetry (DSC) , polarizing optical microscopy (POM),and thermogravimetric analysis (TGA). The monomer MLC exhibited enantiotropic broken fan- shaped of a chiral smectic C (SC*) phase, and oily streak texture and focal conic texture of cholesteric phase on heating and cooling cycles. The crosslinking agent CA showed fan-shaped texture of a smectic A (SA) phase and thread texture of nematic phase. The elastomer LCEshowed cholesteric Grandjean texture because of the introduction of the nematic crosslinking unit. This indicated that lightly crosslinked elastomer showed the basic features of polymeric networks with anisotropic physical properties with reversible phase transition during heating and subsequent cooling. The glass transition temperature and clearing temperature of LCEwere 10. 5 and 176. 2℃,respectively. TGA showed that LCEhad a good stability, and the temperature at which 5% weight loss occurred was 339℃.关键词：Chiral;Liquid crystalline;Monomer;Crosslinking agent;Elastomer
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发布时间：2022-09-18 - 摘要：In this article, we successfully prepared polyimide (PI) microspheres via polymerization, following the two- steps imidization. The microstructure, morphology, and thermal property were characterized by infrared spectroscopy (FT- IR),scanning electron microscopy (SEM),and thermogravimetric analyzer (TGA),respectively. The results showed the addition of LiCl to PAA-DMF solutions had s significant effects on PI microspheres morphology. At a given polymer concentration, the increase of LiCl content reduced the salvation power of DMF for PAA, leading to the increases of PI microspheres porosity and the decreases of pore size. At the higher Li concentrations,the PI microspheres showed finely porous structure with sponge-like. Additionally, the addition of LiCl had no effect on the thermal properties of PI microspheres.关键词：Polyimide;LiCl;Microspheres;Interactions;Viscosity
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发布时间：2022-09-18 - 摘要：Novel guanidine-based antimicrobial polymer with synergistic wet strength and antimicrobial activity was synthesized from Guanidine hydrochloride, hexamethylene diamine,diethylenetriamine and epichlorohydrin. 2D NMR (H- H COSY) was used to characterize the molecular structure of the synthesized polymer. The minimum inhibition concentration of the guanidine-based antimicrobial polymer was investigated as well as its effect on increasing the wet strength of paper. The UV absorption measurements and confocal laser scanning microscopy were also used to further explore the antimicrobial mechanism of it. It was found that the antimicrobial guanidine-based polymer inhibited the growth of bacteria by destroying cell membrane of bacteria and causing the leakage of intracellular components from cells.关键词：Antimicrobial polymer;Wet strength;Antimicrobial mechanism;Confocal laser scanning microscopy
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发布时间：2022-09-18 - 摘要：Polypropylene has become one of the most widely used and rapidly growing general plastics, but its application is restricted in some areas owning to its non-polarity. Grafting polar monomers to the PP main chain is one of the most effective methods to improve its polarity. There are several common methods,such as high-energy radiation grafting, UV-induced surface grafting, plasma, controlled/living polymerization, supercritical CO2 assisted grafting etc. Among these methods, supercritical CO2 assisted grafting has been widely applied because of its good solubility to monomers, good swelling ability to polymer matrix, non-toxic,non-flammable,and relatively low cost. In this paper, advances in supercritical CO2 assisted grafting of polypropylene in solid phase were systematically reviewed in several aspects, such as grafting mechanism, selection of monomers,impact factors and application of supercritical CO2 assisted grafting of polypropylene.关键词：Supercritical CO2;Solid grafting;Polypropylene;Grafting monomers;Impact factors
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发布时间：2022-09-18 - 摘要：The principles and methods of lignin reinforced emulsion styrene-butadiene rubber have been elaborated. The principles include reaction of rubber grafted lignin,aromatic hydrogen bond formation of lignin and rubber and chelate formation of lignin and metal ions. The methods include mixing process, co-precipitation process etc. Then the research progresses and application are summarized at home and abroad. The results show that the mechanical properties of rubber were well improved by lignin added, such as hardness of rubber, tensile strength, elongation at break, modulus at 300%, tear strength, thermal aging resistance and so on. At last the preparation of lignin were put forward.关键词：Lignin;Rubber;Reinforce;Accessory ingredient
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发布时间：2022-09-18 - 摘要：The author attended some undergraduate courses of Department of Chemical Engineering at McMaster University in Canada during her visiting. The teaching methods and teaching skills of the course, "Introduction of Polymer Science", are good to us to learn because it was not only represented the teaching level abroad, but also contributed good experiences. Many kinds of teaching methods and teaching skills which were used in this course, such as teaching method, discussing method, teaching-show method, practicing method, task-driven method, reading guidance method, game incentive acting or rewarding method, conminucating online method, teaching assistant method, were introduced in detail and illustrated by examples. Hope it was useful for domestic peer to teach some other related courses.关键词：Introduction to polymer science;Teaching;Teaching methods;Teaching skills
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发布时间：2022-09-18
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